Engine test apparatus



Nov. 20, 1962 P. .1, .STEVKO, JR ,4

ENGINE TEST APPARATUS Filed Feb. 2, 1959 2 Sheets-Sheet l IllllllllllllllIlllllllllllllllll I} gul- INVENTOR.

PHILLIP J. STEVKO JR.

ATTORNEYS 52 P. .1. STEVKO, JR 3,064,470

I ENGINE TEST APPARATUS Filed Feb. 2, 1959 2 Sheets-Sheet 2 15 n V 3 SPEED 32 as L L2 65 CONTROL DYNAMOMETER l, T r\ l se P69 INVENTOR.

77 :4 PHILLJP J. STEVKO JR.

OM85; 201%,; Dow/mil AT TORNEYS United States Patent Ofilice 3,954,479 Patented Nov. 29, 1952 3,964,470 ENGINE TEST A?PARATU Phillip J. Stevlro, J12, Euclid, Ohio, assignor to The Standard Oil Company, Cleveland, (Plain, a corporation of Ohio I Filed Feb. 2, 1959, Ser. No. 790,742

1 Claim. (Cl. 73-116) This invention relates to multiple-point positioning mechanism especially suited for use as a throttle control device in the automatic operation of test engines through recurring cycles of various pre-chosen speeds.

Such engine test apparatus usually employs an electrical dynamometer having an automatic speed control, with the latter operative to maintain constant speed by decreasing or increasing the load on the engine under test. In this type of system, which is well-known, the throttle on the engine must be suihciently open for the speed control to take over, that is, the engine must have sufficient initial speed, and to put a desired load on the engine, the conventional speed control device is set at a desired speed and the throttle is then advanced until the desired load appears. Automatic control of such operation is highly desirable, particularly where the recurring speed cycle is of relatively short duration, and this will be seen to require adjustment of the throttle position with and in predetermined relation to shifts from one speed to another in the particular operating cycle.

To illustrate further the type of programming involved in such automation, a typical speed cycle might comprise four stages, as follows: a first stage in which the engine runs for thirty seconds at 450 rpm. without load; a second stage of operation for thirty seconds at 1690 rpm. and under a load of twenty pounds beam; a third stage of ten seconds duration with the engine running at 150% rpm. under fifteen pounds beam load; and a fourth stage of operation for twenty seconds at 2606 rpm. without load. The several stages of course are immediately consecutive and the total time of this particular cycle will be seen to be ninety seconds, with the cycle repeated continuously for as long as desired.

it is a primary object of the present invention to provide a system for full automatic control of such engine test procedure.

Automation of the engine throttle control will be seen to present a problem of linear postioning, and a further object of the invention is to provide a system as aforesaid characterizcd by novel and improved linear positioning mechanism for such a itomatic adjustment of the engine throttle. Such mechanism, having Utliily in other multipoint positioning installations as well, is in the nature of a solenoid control disting-L shed by its small number of components, with consequent advantages in respect of equipment costs, space requirements, and the like in this last connection, a conventional treatment of a linear positioning problem would call for a solenoid operated de ce and its governing relay for each of the desired positions. As will be more fully described hereinafter, the mechanism of my invention requires only two solenoids and respectively associated relays to provide four linear positions.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of out a few of the various ways in which the principle of the invention may be employed.

in said annexed drawings:

PEG. 1 illustrates in elevation a conventional form of engines test apparatus including an electrical dynamorneter;

FIG. 2 is a side elevation of my improved linear positioning mechanism here provided for automatic control of the engine throttle in such test apparatus;

FIG. 3 is a simplified View of such mechanism in which its multiple conditions of actuation are illustrated; and

FIG. 4 shows a system for automatic control of the test aparatus in accordance with the present invention.

Referring now more particularly to the drawings, FIG, 1 illustrates an entirely conventional engine test stand in which the engine, designated generally by reference numeral ll), is connected to an electrical dyna mometer 11. As previously indicated, the latter is a generator, and the stator 12 is rotatably supported on trunnion bearings 13, with an appropriate scale, not shown, appropriately attached t tie stator to indicate any torque efiect. The rotor of the generator is of course mounted on the shaft driven by the engine and the internal magnetic structure is such as to develop force tending to turn the stator.

Excitation of the field of the dynomometer is here provided by a controllable enciter l5 driven by the main shaft, and the torque of the dynamorneter is controlled by regulating the exciter energization. Both the structure and mode of operation of such a unit are well understood by workers in the art, and the particular dyanomorneter which has been illustrated is one supplied by The Mid-West Dynamometer and Engineering Company, so that further detailed description thereof is obviously unnecessary.

The throttle control rod of the engine is shown broken at 16 in FIG. 1 and in FIGS. 2 and 3 as connected at its removed end t my new positioning device. Such device comprises a support in the form of a vertical plate 17 having front and rear flanges it? and 19 respectively. Two solenoids ill and 21 are mounted horizontally one above the other against the inner face of the rear flange 19, with the armature 2-2 of top solenoid directly above and extending parallel to the armature 23 of the bottom solenoid. 21.

An extension rod 2 is inserted in an axial hole provided therefor in the end of the armature 22 and held in place by means of a cotter key 25 passed transversely through the armature an opening in the thus inserted end portion of the rod. Another extension rod 26 is similarly attached to the lower armature 23, and secured in like manner by a further cotter key 27. The outer ends or" the two rods 24 and s are received respectively in the slotted ends of a link 25, with the rod ends pivotally connected to the link by means of cotter keys 23 and 3h.

The link is thus supported by the extension rods, and a central aperture 31 is provided in the same. A control rod 32 of smaller diameter extends through such aperture and forwardly through an also enlarged hole 33 in the front flange E8 of the support. The inner end portion of this rod. 32 is provided with a series of holes 34 and is pivotally attached to the link 28 by means of a cotter key 35 passed through the latter and through one of the holes 34. A bolt 36 is threaded through the support front flange 33 along the axis of the top solenoid armature 2'2, and a second bolt 37 is likewise held in this flange on the axis or" die bottom solenoid armature 23, the heads of the two such bolts being innermost and serving, as will be more fully described hereinafter as adjustable stops or limits for movement of the link 28 under the infiuence of the solenoids.

The control rod 32 extends forwardly of the positioning mechanism and is attached through a yoke connector 38 to the free end of the throttle rod 16. A spring 39 is connected between the yoke and a stationary surface indicated at 4% under tension to urge the throttle rod and connected control rod 32 forwardly, or to the right as viewed in FIG. 2.

With reference now to FIG. 3, the stops 36 and 37 have been adjusted in the flange 18 so that the spring 39 is operative to bring the link 28 against the same in the fully de-energized condition of the mechanism, with the upper stop 36 projecting inwardly further than the lower stop 37 and the link therefore at an angle (this condition being shown in full lines). The center of the link 28 thus lies on a vertical reference line 41 which denotes a first position of adjustment.

If the top solenoid is now energized, with the bottom solenoid remaining de-energized, the armature 22 moves to the rear, pivoting the link 28 at its lower end bearing against the stop 37 to the angular position shown by the dashed outline 42. Such shifting of the link moves the center connection of the control rod 32 to the same inwardly linearly to the reference line 43 which indicates the second position of adjustment of the mechanism.

A third position is realized by energizing the bottom solenoid 21, with the top solenoid de-energized, thereby to pivot the link 23 against the upper stop 36 to the angular position shown by the dashed outline 44. This shifting of the link moves the control rod connection thereto further inward to a point occurring on the reference line 45. Finally, the two solenoids can be simultaneously energized to draw the link to the position shown by the dashed outline 45, further shifting the control rod connection in the same direction to coincide with the vertical reference line 47.

'With the device in the illustrated de-energized condition, it will be noted that the inner movement or stroke of the upper armature upon energization is less than the stroke of the lower armature, and the distances that they are thus capable of moving are relatively small as compared to the total effective length of the connected link. The linear distance between the first and second positions of adjustment is accordingly approximately equal to the stroke of the armature 22 times the ratio of distance between the link pivot points 23, 35 to the distance between the link points 29, 30 and, similarly, the linear distance from the first to thethird adjusted positions is approximately equal to the stroke of the armature 23 times the ratio the distance between the link pivots 35, 30 to the distance between the points 29, 30. The linear distance between the first and fourth positions of adjustment is approximately equal to the sum of the distances moved in the second and third positions; 7

It will thus be seen that this mechanism, using only two solenoids, is operable to provide four positions of linear adjustment. The fourth position is, as explained above, dependent upon the first, second and third positions, so that the device has three independent positions and one dependent position.

The application of the positioning mechanism to the automatic control of an engine test stand such as illustrated will be evident from the system of FIG. 4, wherein the dynamometer speed is timer controlled and the energization of the positioning solenoids is responsive to this speed regulation. The latter is accomplished by means of four potentiometers 48S-1 shown as commonly connected across a direct current voltage source indicated at 52. Potentiometer 43 is adapted to supply a predetermined voltage to the speed control device 15 of the dynamometer 11 by connection thereto through a switch 53 operated by .azrelay 54 the energization of which is controlled by a a switch 55. Each of the other potentiometers is operative shown as being energized,

in like manner to provide difierent speed control voltages,

with the circuit for potentiometer 49 including switch 56 operated by relay 57 in turn controlled by switch 53, pctentiometer 50 so connected by switch 59 of relay 60 energized through a switch 61, and the last potentiometer 51 supply circuit including switch 62 operated by relay 63 which is energized through a switch 64. The relays are through their respective switches, by a source represented by the conductors L and L and the several switches 55, 58, 61 and 64 are automatically actuated by a suitable timer or sequence controller 65 of known available type, whereby the dynamorneter speed is regulated in accordance with a predetermined time cycle.

A separate alternating current source 66 is provided for energization of the solenoids 2t} and 21 of the linear positioning mechanism under control of switches actuated by certain of the aforesaid relays. Thus, the solenoid 20 is connected to the source 66 by closure either of switch 67 operated by the relay 57 or by switch 68 operated by the relay 63. This last relay also actuates a switch 69 for connecting the solenoid 21 to the source 66, while a separate switch 70 operated by the relay 60 can also be closed to complete the energization circuit of the solenoid 21.

This interrelation of the speed control and throttle positioning systems is such that when the relay 57 is energized by the timer 65, so that potentiometer 49 delivers the speed control voltage, switch 67 is closed simultaneously to energize the solenoid 2t). Shifting to the potentiometer 50 by energization of the relay 60 also closes switch 70 to energize solenoid 21, while operation of the relay 63 to render the potentiometer 51 operative results in both solenoids 20 and 21 being energized. Such operation accounts for three throttle positions, while the fourth position is that which obtains when both solenoids are de-energized, as aforesaid, and this condition can correspond to the control setting derived from the remaining potentiometer 48.

In setting up the system for the desired cycling, the speed of the internal combustion engine in the several desired phases is adjusted by means of the otentiometers, while the load is adjusted by means of the connection of the throttle rod to the positioning mechanism and by adjustment of the bolts or stops of the latter. For example, in an illustrative three phase cycle, the timer is set to the position in which both solenoids are energized and the operative speed control potentiometer adjusted to provide 2100 r.p.m.; the connection of the throttle rod to the control link is then adjusted to provide a beam load of thirty-four pounds. The second phase potentiometer is next set to provide a speed of 1000 r.p.m. when one solenoid is energized and the stop opposite the other solenoid (which provides the pivot for the lever or link in such condition) is adjusted in and out to give the proper load at this speed, e.g. 17.4 pounds under beam.

The third phase potentiometer is finally set to provide 1500 r.p.m. when the other solenoid is energized and again the load at this speed, e.g. 22 to 25 pounds beam, is determined by adjusting the stop against which the link bears in this operative condition.

The foregoing example serves to demonstrate the adjustability of the illustrated embodiment of my new linear positioning mechanism, and the various adjustmnts are of course available regardless of the specific nature of the controlled unit. That is, such adjustments determine the relation of the multiple positions of the control linkage, whether the latter be connected to a throttle or some other device the operation of which involves linear positioning.

It will also be appreciated that the unbalanced action of the solenoids individually can be realized by expedients other than the unequal stop spacing described, the significant characteristic in this regard being that the movement of the linkage in response to energization of one solenoid should not be the equivalent of the movement produced by energization of the other solenoid. Even with the preferred stops, it would of course be possible t spring bias the assembly to a relatively retracted condition with the armatures moving forwardly upon solenoid energization rather than to withdrawn positions as described.

Gther modes of applying the principle of the invention may be employed, change being made as regards the details described, proyided the features stated in any of the following claims or the equivalent of such be employed.

I, therefore, particularly point out and distinctly claim as my invention:

In test apparatus including an internal combustion engine and an electric dynamometer connected thereto, linear positioning mechanism connected to the throttle of said engine comprising a support, two side-by-side solenoids mounted on said support, a link having its ends pivotally connected respectively to the armatures of said solenoids, a control rod pivotally connected to said link at a point intermediate such end connection thereof, adjustable screw stops mounted on said support and arranged respectively opposite the solenoid armatures to limit movement of the link ends, said stops being axially adjustably positioned at different spacings from the respectively opposed armatures thereby limiting the movement thereof, spring means for biasing the link outwardly against said stops, a source of electrical energy, and control means for connecting the solenoids to said source, said control means having three conditions of adjustment for respective connection of each solenoid alone and both simultaneously to said source, whereby said control rod has one adjusted position when both solenoids are de-energized and three further adjusted positions corresponding to the different conditions of energization of said solenoids.

References Cited in the file of this patent UNITED STATES PATENTS 1,508,353 Scott Sept. 9, 1924 1,788,787 Wilhjelm Jan. 13, 1931 2,924,095 Worstell Feb. 9, 1960 

